The Embryonic Stem Cell/Transqenic Mice (ES TGM) Shared Resource was reorganized in 2003, under the direction of Dr. Hong Wu (STT and GU) and the co-direction of Drs. Xin Liu and Meisheng Jiang. UCLA has provided new space for the ES cell facility and for the injection facility. The ES/TGM Shared Resource produces targeted genetic alterations in embryonic stem (ES) cells, knock-in mice, knock-out mice and transgenic mice for its clients. The Shared Resource also provides re-derivation services. Drs. Wu, Liu and Jiang provide consultation in vector design, experimental design, analysis of recombinant ES cells and analysis of chimeric offspring. The shared resource is designed to be as turn key for the investigator as possible. The ES service provides a series of alternative vectors for knock-in and knock-out constructs, ES cell lines, irradiated feeder cells, tested sera, mycoplasma testing, electroporation services and cloning of ES targeted cells. Investigators prepare the targeting vector, drop it off and identify appropriate clones by Southern blotting and/or PCR. Appropriate clones are delivered by the ES facility to the injection facility for blastocyst injection and investigators characterize progeny for germline transmission by genetic analysis of tail clips provided by the Shared Resource. The Transgenic facility also prepares transgenic mice with plasmid, BAG, and lentiviral vectors. Inbred strains are available for appropriate back crossing. The directors and the technical staff are experienced and experts in their fields. Turn-around times for ES cell delivery and for transgenic mouse delivery are close to the minimum times possible for the biological processes. Homologous recombination to produce targeted ES cell clones has been 100% successful and generation of genetically modified mouse strains is greater than 95%. The Shared Resource also works to establish new technologies and to integrate state-of-the-art advances (e.g., use of BAG and lentiviral vectors) into procedures available to clients. During the current CCSG cycle the ES/TGM Shared Resource has created 74 targeted strains and 85 transgenic strains; 24 Cancer Center members representing seven Program Areas have utilized the services of the ES TGM Shared Resource during the current CCSG cycle, to produce 65 percent of these mice. (Please also see Section 6,2.3 on Shared Resources in the History, Description, Essential Characteristics). 18 Cancer Center members representing 7 Cancer Center Program Areas utilized the services of the Embryonic Stem Cell/Transgenic Mouse Shared Resource during the reporting period. This is a continuing shared resource.